In situ formed copper nanoparticles via strong electronic interaction with organic skeleton for pH-universal electrocatalytic CO2 reduction

Abstract

Electrochemical CO₂ reduction reaction (CO₂RR) has mainly been implemented in alkaline and neutral electrolytes. However, part of the input CO₂ is consumed by the formation of carbonate, which leads to lower carbon utilization efficiency and significant energy losses. Acidic media can overcome these shortcomings but is less investigated since hydrogen evolution reaction (HER) is hitherto dominant and only few catalysts show excellent performance. Herein, we report an in situ formed novel organic/inorganic copper hybrid catalyst that originates from histidine-functionalized perylene diimide (HPH) coordinating with copper ions for CO₂RR in acidic media. HPH contains two symmetrical imidazole, which has the ability to supply electrons to copper ions, creating electron-rich Cu at applied voltages. The spilled Cu⁰ forms a hybrid structure with the HPH ligand that exhibits pH-universal electrochemical CO₂RR activity and FE_CO could reach approximately 70% in acidic, alkaline, and neutral electrolytes. In situ ATR-SEIRAS and XPS spectra indicate that the organic/inorganic copper hybrid catalyst formed by in situ reduction can be conducive to promote the activation of CO₂ molecules and enhance the adsorption strength of the *COOH and *CO intermediates, especially in acidic media.